Metastin (45-54) is a decapeptide with C-terminally amidated LRF-motif which acts as a potent and selective agonist of AXOR12 (GPR54, a novel human G-protein-coupled receptor). Metastin (45-54) induces an increase in intracellular Ca2+ levels in CHO/h175 and CHO/AXOR12:Gqi5 cells and exhibits about 8-fold higher receptor binding affinity (Ki = 42 pM) compared to Metastin.